Door operator



Nov. 18, 1958 E. v. SCHNEIDER DOOR OPERATOR 2 Sheets-Sheet 1 Filed Jan.19', 1955 gar/Ill,

INVENTOR. EMMOR V. SCHNEIDER W E. V. SCHNEIDER DOOR OPERATOR 2Sheets-Sheet 2 Filed Jan. 19, 1955 INVENTOR.

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EMMOR V. SCHNEIDER BY a/ l v 9 mm 2 F 2 mm O O NE 2. n B m o k B k o 0 &o o @w 8 Mllnlllll' OOOOOOOOOOOnwmOOmO O OOO OO OOOOOOO @O I 3 :v o oo00 000 o o 000 o ooooQOQa n E .1 2 mm ,W N 1 2 [6 T m om .8 8 5 UnitedStates Patent DOOR OPERATOR Application January 19, 1955, Serial No.482,763 9 'Claims. (Cl. 268-59) The invention relates in general to dooroperators and more particularly to latch means for connecting anddisconnecting a garage door from a drive means. The invention alsorelates to connecting and disconnecting drive and driven members bymeans of a movable latch which has difierent resistances to movement inthe latched and unlatched conditions which may be overcome by theapplication of suitable forces. The driven member has a resistance tomovement which may be overcome by a force applied by the drive member.The numerical value of the normal resistance is smaller than the valueof the latched resistance and larger than the value of the unlatchedresistance.

It has long 'been desired to have a garage door opener which may bedriven by a uni-directional power source without the use of a slippingclutch or other equivalent means to disconnect the driven member fromthe driving means in the event an obstruction might be encountered bythe garage door in its travel between an open and a closed position.They have also been desirous of obtaining a door opener driven by apositively geared unidirectional power source, which will unlatch uponreaching an open position and which will automatically latch when it isdesired that the door be closed. The reverse is also desirable, namelythat the door opener will unlatch upon reaching a closed position andwill latch when the door is to be opened. I i

The use of a single or uni-directional power source and a positivelygeared drive train are desirable because of the economics involved intheir manufacture and the ease in their installation. v

An object of the invention is to provide latching means in a garage dooropener which will permit relative movement between a carriage which isattached to a garage door and a continuous chain.

Another object of the invention is to provide a garage door opener witha single carriage which carries a latch sprocket assembly and acontinuous chain which has lug means whereby the chain engages and movesthe carriage to one end of a guideway where the carriage abuts a stopand whereafter the chain disengages the carriage and rounds a member towhich it is supported and thereafter re-engages the carriage and movesit in another direction to another end of the guideway.

Another object of the invention is to provide a door opening mechanismhaving a positive drive from a unidirectional power source, withlatching means which pro- ,vides for unlatching the door from the powersource when the door is up and provides for latching the door to thepower source when it is desired that the door be closed.

Another object of the invention is to provide a con-,'

tinuous chain which is driven from a positive uni-directional source andwhich travels in two substantially linear paths and two substantiallyone hundred eighty degree paths, with lug means for connecting the chainthrough latch means to a carriage which is in turn connected to a doorto be opened and closed whereby the chain and the carriage will becomedisconnected after the carriage and chain travels through one of the twosubstantially linear paths and when the door reaches the open positionand the lug means will thereafter traverse one of the one hundred eightydegree paths and become re-connected to the carriage and the carriagewill then be transported in the other substantially linear path untilthe door is in the closed position or until the door engages anobstruction.

Another object of the invention is to provide safety means in a doorlatching mechanism whereby a carriage connected to a door is preventedfrom escaping from lug means on a chain which is moving the carriage andthe door, while the door is traveling between open and closed positions.

Another object of the invention is to provide latching means wherebymovement of a driven member is transmitted to another member until apredetermined resistance to movement is developed by the other memberwhereby relative movement may be etfected between the driven member andthe other member.

Another object of the invention is to provide latching means which willdisconnect a chain which is moving a door between open and closedpositions when the door or a part thereof meets a predeterminedresistance to movement.

and claims, taken in conjunction with the accompanying drawings, inwhich: v

Figure 1 is an elevational view showing a garage .door opener connectedto a garage door and showing'injfull lines the position of the door whenopen and showin g'in dotted lines the position of the door when closed;7 A v Figure 2 is an enlarged sectional view of the latch means takenalong the lines 22 of Figure 4, which connect a chain drive to a garagedoor and is shown just as the door reaches the open position; I

Figure 3 is an enlarged sectional view of the latch means of Figure 2shown subsequent to the door reaching-the open position; l

Figure. 4 is a view taken generally. along flJe lines 4-4 of Figure 2;

Figure 5 is an enlarged view partially in section showing principally adiflerent latch means which may be used in the invention; p

Figure 6 is another view showing a further modification of the latchmeans utilized in this invention; and

Figure 7 is a view showing a still further modification of the latchmeans astaught by the invention.

Figures 1 and 2 show generally a motive power source 10 driving acontinuous chain 11 and latch means indicated generally at 12. The latchmeans "12 is mountedfor travel in a guideway 13 and connects anddisconnects garage door 14 to the chain 11. The guideway 13 and thepower source 10 are connected to a ceiling 16 of a building in whichthey are to function, by suitable means such as bolts 17. The powersource 10 is a single or unidirectional power source as taught by thisinvention, but it will be apparent that a bi-directional power sourcemight be used if one so desired. The motive power source 10 is designedto deliver by way of the chain 11, a predetermined force of a least afirst numerical value.

The guideway 13 has a first and a second end portion indicated by thereference numerals 20 and 21, respectively. A first sprocket wheel 24 ismounted at said first end portion 20 of the guideway 13 and a secondsprocket wheel 25 is mounted at the second end portion 21 of theguideway. The chain 11 or driving member is carried by the sprocketwheels 24 and 25 and is driven in its movement about these sprocketwheels by means of a gear wheel 27 intermeshing with a worm gear 28which is in I turn connected to the. motive power source 10. The

Other objects and a fuller understanding of this invention maybe had byreferring to the following description an electric motor. A switch armwhich leads to a switch 31, shown in Figure 2, connects the power source10 to a source of electric current, not shown. The chain or first member11 has a first and asecond substantially straight run portion indicatedgenerally by the reference nume als 34 and 35 respectively acrosswhi'cnnie chain 11 is adapted to travel in a first and a seed ridsubstantially linear direction respectively. The firstahd'second'liheardirections are indicated by the arrows 37 and38 res ectively. The chain11 also travels through two substantially one hundred eighty degreepaths as it rounds the first and' second sprocketwheels 24 and 25respectively. These paths are indicated generally by the numerals and 42respectively. The guideway 13 as shown inthe accompanying drawings maybe of any suitable form and hasb'een shown merely'by Wayof example as acircular pipe which is slotted along its underside for a distance whichis the greaterpart of the length of the pipe. A carriage orsecondmernber is mounted within the guideway 13 and :is" adapted formovement within the guideway in the above-mentioned first and secondlinear directions 37 and 38 respectively. Connection means 43 ,areprovided for connecting the carriage or driven metn derdo t egaragefloor 14 whereby movement of thec'arriageAO' imparts movement tothe door 14. The doof14 'is' shown only partially in Figure 1. Theconnectiddmesns 43 include generally a downwardly extending flange .45which extends from the carriage or diiven member 40, 'aiioff ce nterlocking arrri46 pivotally conneerdto'thensd e at 51, a shock absorbertype snubber 47coriiiect'ed to' the off-center locking arm and a doorarm 48, The door arm 48 is attached at one end to the sriubber 47 anatthe other end at 52 to an adjustable doorfbrfacket'49 which in turn isfixedly attached to an upper portionbfthe garage door 14 by suitablemeans such as b'y'th bolts 50. The garage door 14 is made up of sections55, an 5,6 which are hinged together by a hinge 57. "A'fshaft 58eikt'ends through the hinge 57 and thus" eoiriplefely connects the doorsections 55 and 56 together and a roller 59 is attached to the end ofthe shaft 58. Aslwill be noted in Figure 1, in the dotted line positioniiidicating the position of the door when closed, the points ofconnection, 51 and 52, are otfcente'r or not in thes'ar'neperpendiciilar' plane. This feature is to prevent strangers frompushing the door open from the out side, when 'the dooris'in this closedposition.

A track 60 is adapted to receive the roller 59 whereby the garage doorissupported and guided in its movement between the open and 'closedpositions. The latch means 12 resides within the carriage'40 and iscarried therewith. The principal function of the latch means is tomaintain either a latched or an"iinlatc'hed condition between the chain11 and the carriage 4t) and hence the door 14. The latch' means 12includes a latch sprocket assembly indicated generally at "and holdingmeans indicated generally' at 66. The latch sprocket assembly 65 ismounted for rotation upon a'sh'aft '67 which is in turn journalledoii'the carriage 4Q. V v v The latch sprocket assembly '65 co'mpr'is'esa' rotatable or arcu'ately movable member which has a first' and asecond oppositely disposed side portion 71 and. 72 respectively and anintermediate annular portion 73'disposed between the firstand secondoppositely disposed side portions, as best seen'iri Figure 4. The firstand second oppositely disposed "side portions have outer pe ripherieswhich are defined by teeth or projections thereon and these teeth on thefirst and second side portions are disposed substantially opposite toeach other thus making up pairs of oppositely disposed teeth. Theseteeth or projections are identified by the numerals 77 through 82 formore casein referring to them hereafter.

The annular portion 73 comprises alternately spaced first surface areasor locking surface areas 85 and second surface areas or a'rcu'atesurfacearea's"86. The locking surface area 85 includesan angular surfaceareas: and

' portions 71 a flattened surface area 88. The holding means 66 includesgenerally a holding member or plunger 90 and spring means 91. Theholding member 90 has surface means comprising a first surface 92adapted to engage the first surface or flattened surface and a secondsurface 93 adapted to engage said angular surface 87 when the latchmeans 12 is in the latched position. The latched position is illustratedmost clearly in Figure 2. The spring means 91 is adapted to urge theplunger toward the intermediate annular'portion 73 ofthe latch sprocketassembly 65. The above-described elements in the latched positioncomprise means for establishing the first resistance to rotation of thelatch sprocket assembly. A force of a first value is required toovercome this first resistance to rotation of the latch sprocketassembly and thereby rotate the latch sprocket assembly. When the latchmeans 12 is in the unlatched condition, as best shown in Figure 3, thefirst surface 92 of the plunger engages the arcuate surface 86 whereby athird resistance to rotation of the latchsprocket' assembly 65 iseffected. The above-described elements in the unlatched positioncomprise means for establishing the third resistance to rotation of thelatch sprocket assembly. A force of a third value is requir'ed toovercome this third resistance to rotation of the latch sprocketassembly and thereby rotate the latch sprocket assembly.

A firstadjustable stop means 95 is mounted at the first endportion 20 ofthe guideway 13 and a second stop means 96 is mounted at the second endportion 21 of the guideway 13. The stop means '95 may be adjusted withinlimits for variations in different garage door lengths. The stop means95 and 96 limit the movement of the carriage 40, in the above-mentionedfirst and second linear directions 37 and 38, respectively, within theguideway 13. The continuous chain 11 is made up of a series ofinterconnecting links 94 which are adapted to travel between theoppositely'dis'posed teeth on the first and second side and 72 of thelatch sprocket assembly 65 and adjacent the intermediate annular portion73. Lug means comprising afirst and a 'sec'ondchain lug indicated by thereference numerals 97 and 98 respectively are mounted upon thecontinuous chain 11 and as best seen in Figure 4, are of a greaterlength than the distance between the first and second side portions 71and 72 of the latch sprocket assembly 65 and thereby engage theoppositely disposed teeth on the latch sprocket assembly.

A switch actuating member 99 is carried by the chain 11 and is spaced apredetermined distance from the chain lugs and is adapted to engage theswitch arm 30 which in turn actuates the switch 31 and thus energizesand deenergizes the power source 10. The carriage 40 has a second and afourth resistance to movement within the guideway 13. The secondresistance to movement stems from the weight, inertia, and frictioninvolved in the carriage 40, connection means 43 and the door 14, eventhough these elements are partially balanced by counterweights ortension springs of some type. This might be referred to as the normalfree-running resistance to movement of the carriage and the door. Thissecond resistance requires a force of a second value to overcome it andthus start the carriage moving or to keep it moving when once started.The fourth resistance to movement of the carriage 40 stems from thecarriage, door or some part there of striking an object in the path ofits travel either accidentally placed there or placed there purposely asa permanent stop.

The numerical value of the above-mentioned force of a second value whichis required to overcome the second resistance to movement of thecarriage is less than the numerical value of the force of the firstvalue which is required to overcome the first resistance to rotation ofthe latch sprocket assembly and is greater than the numerical v'alueofthe force of the third value which is required toovercom'e the thirdresistance to rotation of the latch sprocket assembly. The fourthresistance to the force of .thefirst value. The second resistance tomovement of the carriage 46 is'greater than the third resistance tomovement of the latch sprocket assembly and less than the firstresistance to movement of the latch sprocket assembly. The fourthresistance to movement of the carriage 40 is greater than the force ofthe first value. In other words, the fourth resistance prevents movementof the carriage 40 sufficiently so that the force from the motive powersource acting through the chain and the lug means to the latch sprocketassembly contributes an effective force of the first value to rotate thelatch sprocket assembly rather than contributing the entire force to themoving of the carriage. As shown best in Figure 2, the first chain lug97 and the second chain lug 98 surround the tooth indicated by thenumeral 77 when the latch means is in they latched, position and sincethe resistance to movement of the carriage 40 and the door 14, otherwisereferred to as. the second resistance or free-running condition of thecarriage and the door, is less than the above-mentioned first resistanceto rotation of said latch sprocket assembly, the movement of the chain11 carries the carriage 40 and hence the garage door 14 across the firststraight run portion 34 in the first linear direction 37 to the firstend portion of the guideway 13.

Figure 2 shows the downwardly extending flange 45 just as it makescontact with the first stop means 95 at the first end portion of theguideway. It will be noted that as the flange reaches this position itactuates a switch 89 which controls an electric light 94. Thesurrounding of the tooth 77 by the lugs 97 and 98 acts also as a safetylatch whereby the carriage and hence the door is prevented from escapingfrom the movement of the chain and possibly striking someone orsomething while slamming shut to the closed position. It will thus beseen that there is no relative movement between the chain and thecarriage while the carriage is traversing the first and second straightrun portions 34 and 35, respectively; As the carriage reaches thelimit'of its movement in the first linear direction as shown in Figure2, the above referred to fourth resistance to movement of the carriage40 is effected and the second chain lug 98 provides the force of thefirst numerical value which overcomes the first resistance to rotationof the latch sprocket assembly and the assembly rotates into theposition as illustrated in Figure 3, thus permitting relative movementbetween the chain 11 and the carriage 40. The switch actuating member 99engages the switch arm 30 at approximately the same time that the secondchain lug 98 causes the rotation of the latch sprocket assembly 65, andthereby deenergizes the motive power source 10. The inertia of themoving parts carries the chain and hence the chain lugs into theunlatched position, as indicated in Figure 3 wherein movement of thechain ceases. As noted in Figure 3, the first surface 92 of the holdingmember 90 is in engagement with the second or arcuate surface .86. Whilein this unlatched condition, there is a third resistance to rotation ofthe latch sprocket assembly. When it is desired that the garage door beclosed, suitable means for re-energizing the motive power source, notshown here, may be provided whereby the first and second chain lugs 97and 98, respectively, are carried around the first sprocket wheel 24located at the first end portion 20 of the guideway 13 and into positionto traverse the second straight run portion 35 in the second lineardirection 38. The normal free running or second resistance to movementof the door 14 and the carriage 40 is greater than said third resistanceto rotation of the latch sprocket assembly 65. The first chain lug 97engages the tooth 79 thereby rotating the latch sprocket assembly intothe latched position thus locating the tooth 78 between the first andsecond chain lugs 97 and 98, respectively; and once in this latchedcondition, the carriage 40 will be transported within the guideway 13 tothe second end Portion 21 of the guideway 13 andthe door 14 will beclosed as indicated by the dotted line position in Figure 1.-

It will be noted that the safety latch feature as mentioned above isalso in effect when the door is beingcarried to the closed position.When the carriage reaches'thesec- 0nd stop means 96 at the second endportion 21 of the guideway 13, the same process occurs as describedabove when the carriage reached the first stop means at the first endportion of the guideway.

The first resistance to rotation of the latch sprocket assembly when inthe latched condition is not so great that a person by grasping the doorand pulling may not overcome this resistance. By predetermining, bymeans of an adjustable stop screw 100, the first resistance to rotation,when in the latched condition, a person may hand operate the door in theevent the power source is unexpectedly destroyed when the door is onlypartially open or closed. It is, of course, obvious that the door may behand operated when completely open or closed since the latch means is inthe unlatched position. This is subject to one exception, however, inthat the door may not be opened from the outside by hand when it iscompletely closed because of the off-center condition of the two pointsof connection 51 and 52.

Figures 5, 6 and 7 are basically illustrations of modifications of thelatch means which maybe utilized as taught by this invention. Figure 5illustrates latch means whereinthe basic change is in the lockingsurfaces which are utilized. In this case, alternately spaced arcuatesurface areas 104 and flattened locking surfaces 105 are utilized upon arotatable or arcuately movable member 106.

Figure 6 illustrates how a single chain lug instead of two chain lugsmay be utilized in this invention. A single chain lug 108 is carried bythe chain 11 and is surrounded by teeth 109 and 110 on a latch sprocketassembly 112. A holding member 113 and a series of locking surfaces 114and arcuate surfaces 115 are similar to those shown in Figures 2 and 3except that the locking surfaces 114 are spaced every sixty'degreesinstead of every one hundred and twenty degrees as in Figures 2 and 3.This is the case since a complete cycle from latched to unlatched andback to latched position requires a rotation of the assembly 112 throughan angle of only sixty degrees rather than one hundred twenty degrees. I

Figure 7 follows generally the same construction as that used in Figure6, except that a different type chain lug 118, and a latch sprocketassembly having only three teeth 119, and 121, instead of six teeth asillustrated hereinbefore, have been utilized.

As stated above, these modifications are illustrated to show variationsin construction which may be utilized without departing from the :basicteachings disclosed in this invention. 7

It will thus be seen from the foregoing description and operation of theinvention herein disclosed that a new and novel latching means has beenprovided whereby movement of a driven member is transmitted to anothermember until a predetermined resistance to movement is developed by theother member whereby relative movement may be effected between thedriven member and the other member. A few of the safety and conveniencefeatures attendant to the disclosed invention are of course apparentfrom the safety latch feature and the consideration that the door may beoperated by hand in the event the motive power source is destroyed whenmoving the door between an open and a closed position. Among the manyimportant features of this invention is the fact that a uni-directionalmotor or power source may be utilized thus saving money and complexityof wiring in the mechanism.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from'the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

l. A door operating mechanism comprising, a guideway having a first andasecond end portion, a first and a second sprocket wheel located at saidfirst and second end portions of the guideway, a-continuous chaincarried by said first and second sprocket wheels, a positive driveuni-directional power source'adapted to drive one of said sprocketwheels and having an off and on switch, said chain having a first and asecond straight run portion across which said chain-is adapted to travelin a first and a second substantially linear direction respectively, acarriage mounted within said guideway for movement in said first andsecond substantially linear directions, connectionmeans for connecting adoor to be operated to the carriage whereby movement of the carriage istransmitted to the door, latch" means adapted to maintain alternately alatched condition and an unlatched condition between the carriage andthe chain, said latch means including a latch sprocket assembly adaptedfor rotation about an axis, comprising a rotatable member having firstand second oppositely disposed side portions and an intermediate annularportion disposed between said first and second side portions, said firstand second oppositely disposed side portions having outer peripheriesdefined by teeth thereupon, said teeth on the outer peripheries of saidfirst and second side portions disposed substantially opposite eachother therefore making up pairs of oppositely disposed teeth, saidannular portion comprising alternately spaced arcuate surface areas andflattened surface areas, said arcuate surface areas and said flattenedsurface areas connected by angular surface areas, a plunger having afirst surface area adapted to engage said flattened surface area and asecond surface area adapted to engage said angular surface area whensaid latch means is in the latched position, spring means urging saidplunger toward said intermediate annular portion, said latched conditioncreating a latched resistance to rotation of said latch sprocketassembly about said axis, said first surface area of said plungeradapted to engage said arcuate surface area when said latch means is inthe unlatched condition, said unlatched condition creating an unlatchedresistance to rotation of said latch sprocket assembly, stop meansmounted at said first and second end portions of said guideway wherebymovement of said carriage in said first and second linear directionswithin said guideway is limited, said chain being made up of a series ofinterconnecting links which are adapted to travel between the oppositelydisposed teeth-on said first and second side portions of the latchsprocket assembly and adjacent said intermediate annular portion, lugmeans comprising a first and a second chain lug mounted upon said chain,a switch actuating member carried by said chain, resistance to movementof said carriage and said door being less than said latched resistanceand greater than said unlatched resistance, said first and second chainlug surrounding one of said pairs of oppositely disposed teeth on saidlatch sprocket assembly when said latch means is in said latchedcondition whereby said carriage is transported in said first lineardirection within said guideway, said carriage thereafter engaging saidstop means at said first end portion of the guideway thus preventingfurther movement of said carriage in said first linear direction wherebysaid second chain lug overcomes the latched resistance to rotation ofsaid latch sprocket assembly and said sprocket assembly rotates slightlythus moving said latch means to the unlatched condition and thuspermitting relative movement of said chain and said carriage, saidswitch actuating member actuating said off and on switch and therebydeenergizing said uni-directional power source and movement of saidchain ceases, means for re-activating said uni-directional power sourcewhereby said first and second chainlug's are carried around said firstsprocket wheel and in said first into position to traverse said secondstraight run portion in said second substantially linear direction, saidfirst .chain lug engagingianother-pair of oppositely disposed teeththereby rotatingsaid: latch sprocket assembly into a latchedconditionandtthereby surrounding another pair of oppositely disposedteeth. with said first and second chainlug thus positively locking saidcarriage .to said chain, thereafter'the movement of said chain lugs insaid second substantially linear direction transports said carriage 'insaid'second-linear' direction until engagement of said carriagewithsaidstop-means at said second end portion ofthe guidewayds effected.

2. -A door-operating rnechanism comprising, a guideway having a firstand a-second end portion, a first and a second sprocket' wheel locatedat said first and second end portions of the guideway, a continuouschain carried by said firstand secondsprocket wheels, a power sourceadapted to -drive one ofsaid sprocket wheels, a carriage mounted withinsaid: guideway for movement in a'first and a'secondsubstantially lineardirection, connection means for connect-ing a door to be operated to thecarriage whereby movement' of the carriage is transmitted to the door,latch'means adapted to establish a latched condition andan unlatchedcondition between the carriage and the chain, said-latch meansincludinga rotatable member having arcuate surface portions and locking surfaceportions, teeth extending from said rotatable member, a plunger having afirst surface adapted to engage said locking surface portionwhen sa'idlatch means is in the latched position, means urging said plunger towardsaid rotatable membensaid latched condition creating a latchedresistance to rotation' of said'rotatable member, said first surface ofsaid-plunger adaptedto engage said arcuate surface portion when saidlatch means is in the unlatched condition, said unlatched conditioncreating an unlatched resistance to rotation of said rotatable member,stop means mounted at said first and second end portions of saidguideway whereby movement of said carriage in said first and secondlinear directions within said guideway is limited, a first and a secondchain lug mounted upon said chain, resistance to movement of saidcarriage and said door-being less than said latched resistance, saidfirst and second chain lug surrounding at least one tooth on saidrotatable member when said latch means is in said latched conditionwhereby said carriage is transported in said first linear direction,said carriage thereafter engaging said stop means at said first endportion of the guideway thus preventing further movement of saidcarriage linear direction whereby said second chain lug overcomes thelatched resistance to rotation of said rotatable member and saidrotatable member rotates slightly thus moving said latch means to theunlatched condition and thus-permitting relative movement between saidchain and said carriage, means acting in accordance with the movement ofsaid chain whereby said power source becomes de-energized and movementof said chain ceases, means for reactivating said power source wherebysaid first and second chain lugs are carried around said first sprocketwheel and into position to'travel in said second substantially lineardirection, resistance to movement of said carriage and said door beinggreater than said unlatched resistance, said first chain lug engaginganother tooth thereby rotating said latch means into a latched conditionand thereby surrounding another tooth with said first and secondchainlug, thereafter the movement of said chain lugs in said secondsubstantially linear direction transports said carriage in said secondlinear direction until engagement of said carriage with said stop meansat said second end portion of the guideway is effected.

3. A door operatingmechanism comprising, a guideway having a first andasecond end portion, a first and a second sprocket wheel located at saidfirst and second end portions of the guideway, a continuous chaincarried by said first and second sprocket wheels, a uni-directionalpower source adapted to drive one of said sprocket wheels, said chainhaving a first and a second straight run portion across which said chainis adapted to travel in a first and a second substantially lineardirection respectively, a car- 7 'riagemounted within said guideway formovement in said first and second substantially linear directions,connection means for connecting a door to be operated to the carriagewhereby movement of the carriage is transmitted to the door, latch meansadapted to establish a latched condition and an unlatched conditionbetween the carriage and the chain, said latch means including arotatable member having first and second surface portions, projectionsextending from said member, a holding member adapted to engage saidfirst and second surface portions, said holding member engaging saidfirst surface portion when the latch means is in the latched conditionand said holding member engaging said second surface portion when thelatch means is in the unlatched condition, means urging said holdingmember and said first and second surface portions together, said latchedcondition creating a latched resistance to rotation of said rotatablemember and said unlatched condition creating unlatched resistance torotation of said rotatable member, stop means mounted at said first andsecond end portions of said guideway whereby movement of said carriagein said first and second linear directions within said guideway islimited, a first and a second chain lug carried by said chain,resistance to movement of said carriage and said door being less thansaid latched resistance, said first and second chain lug surrounding atleast one of said projections on said rotatable member when said latchmeans is in said latched condition whereby said carriage is transportedin said first linear direction within said guideway, said carriagethereafter engaging said stop means at said first end portion of theguideway thus preventing further movement of said carriage in said firstlinear direction whereby said second chain lug overcomes the latchedresistance to rotation of said rotatable member and said rotatablemember rotates slightly thus moving said latch means to the unlatchedcondition and thus permitting relative movement between said chain andsaid carriage, means for de-energizing said uni-directional power sourcewhereby movement of said chain ceases, means for re-energizing saiduni-directional power source whereby said first and second chain lugsare carried around said first sprocket wheel and into position totraverse said second straight run portion in said second substantiallylinear direction, resistance to movement of said carriage and said doorbeing greater than said unlatched resistance, said first chain lugengaging at least one of said projections thereby rotating saidrotatable member into a latched condition and thereby surroundinganother of said projections with said first and second chain lug,thereafter the movement of said chain lugs in said second substantiallylinear direction transports said carriage in said second lineardirection until engagement of said carriage with said stop means at saidsecond end portion of the guideway is eifected.

4. A door operating mechanism comprising, a guideway having a first anda second end portion, a first and a second sprocket wheel located atsaid first and second end portions of the guideway, a continuous chaincarried by said first and second sprocket wheels, a uni-directionalthereafter the movement of said single drive lug in said power sourceadapted to drive said chain, said chain having a first and a secondstraight run portion across which said chain is adapted to travel in afirst and a second substantially linear direction respectively, acarriage mounted with said guideway for movement in said first andsecond substantially linear directions, connection means for connectinga door to be'operated to the carriage whereby movement of the carriageis transmitted to the door, latch means adapted to maintain a latchedcondition and an unlatched condition between the carriage and the chain,said latch means including a rotatable member having alternately spacedfirst and second surface portions, pro- 10 jections eirtending from saidmember, a holding member adapted to engage said first and second surfaceportions, said holding member engaging said first surface portion whenthe latch means is in the latched condition and said holding memberengaging said second surface portion when the latch means is in theunlatched condition, means urging said holding member and said first andsecond surface portions together, said latched condition creating alatched resistance to rotation of said rotatable member and saidunlatched condition creating an unlatched resistance to rotation of saidrotatable member, stop means mounted at said first and second endportions of said guideway whereby movement of said carriage in saidfirst and second linear directions within said guideway is limited, onlya single drive lug carried by said chain, resistance to movement of saidcarriage and said door being less than said latched resistance, saidsingle drive lug surrounded by two of said projections on said rotatablemember when said latch means is in said latched condition whereby saidcarriage is transported in said first linear direction within saidguideway, said carriage thereafter engaging said stop means at saidfirst end portion of the guideway thus preventing further movement ofsaid carriage in said first linear direction whereby said single drivelug overcomes the latched resistance to rotation of said rotatablemember and said rotatable member rotates slightly thus moving said latchmeans to the unlatched condition and thus permitting relative movementbetween said chain and said carriage, means for de-energizing saiduni-directional power source whereby movement of said chain ceases,means for re-energizing said uni-directional power source whereby saidsingle drive lug is carried around said first sprocket wheel and intoposition to traverse said second straight run portion in said secondsubstantially linear direction, resistance to movement of said carriageand said door being greater than said unlatched resistance, said singledrive lug engaging at least one of said projections thereby rotatingsaid rotatable member into a latched condition and thereby surroundingsaid single drive lug with at least two of said projections,

second substantially linear direction transports said carriage in saidsecond linear direction until engagement of said carriage with said stopmeans at said second end portion of the guideway is effected.

5. A door operating mechanism comprising, a guideway having a first anda second end portion, a continuous chain mounted for movement along saidguideway, a power source adapted to drive said chain, said chain havinga first and a second straight run portion across which said chain isadapted to travel in a first and a second substantially linear directionrespectively, a carriage mounted with said guideway for movement in saidfirst and second substantially linear directions, connection means forconnecting a door to be operated to the carriage whereby movement of thecarriage is transmitted to the door, latch means adapted to maintain alatched condition and an unlatched condition between the carriage andthe chain, said latch means including an arcuately movable member havingfirst and second surface portions, projections extending from saidmember, a holding member adapted to engage said first and second surfaceportions, said holding member engaging said first surface portion whenthe latch means is in the latched condition and said holding memberengaging said second surface portion when the latch means is in theunlatched condition, means urging said holding member and said first andsecond surface portions together, said latched condition creating alatched resistance to move ment of said arcuately movable member andsaid unlatched condition creating an unlatched resistance to movement ofsaid arcuately movable member, first and second means for stopping saidcarriage from movement .whereby movement of said carriage in said firstand chain lug means carried by said chain, resistance-t movement of saidcarriage and said door being lessthan said latched resistance, saidchain lug meanstengagi ng at least one of said projections on saidrotatablemernher when said latch means is in said latched conditionwhereby said carriage is'transported in said first linear directionwithin said guideway said first means for stopping said carriagethereafter preventing furthertmovement of said carriage in said firstlinear direction whereby said chain lug means overcome the latchedresistance to movement of said arcuately movable member and said movablemember moves slightly thus movingsaid latch 'means to the unlatchedcondition and thus permitting relative movement between said chainandsaid carriage, means for de-energizing said power source wherebymovement of said chain ceases, means for re-energizing said power sourcewhereby said chain lug means is carried into position to traverse saidsecond straight run portion in said second substantially lineardirection, resistance tomovement of-said carriage and said door beinggreater than said unlatched resistance, said ch'ain lug means engagingat least one of said projections thereby rotating said rotatable memberinto a latched condition, and thereafter the movement of said chain lugmeans in said second substantially linear direction transports saidcarriage in said second linear direction until said second means forstopping the carriage prevents further movement of said carriage in saidsecond linear direction.

6. A door operating mechanism comprising, a guideway having a first anda second end portion, a first and a second sprocket wheel located atsaid first and second end portions of the guideway, a continuous chaincarried by said first and second sprocket wheels, a power source adaptedto drive said chain, saidchain having a first and a second straight runportion across which said chain is adapted to travel in a first and asecond substantially linear direction respectively, a carriage mountedfor movement in said first and second substantially linear directions,connection means for connecting a door to beoperated to the carriagewhereby movement of the carriage is transmitted to the door, latch meansadapted to maintain a latched condition and an unlatched conditionbetween the carriage and the chain, said latch means including anarcuately movable member having first and second surface. portions,projections extending from said member, a holding member adaptedtoalternately engage said first and second surface portions, said holdingmember engaging said first surface portion when the latch means is inthe latched condition .and said holding member engaging said secondsurface portion when the latch means is in the unlatched condition,means alternately urging said holding member and said first and secondsurface portions together, said latched condition creating a latchedresistance to movement of said arcuately movable member and saidunlatched.condition creating an unlatched resistance to movement of saidarcuately movable member, stop means limiting the movement of saidcarriage in said first and second linear directions within saidguideway, lug means carried by said chain, resistance to movement ofsaid carriage and said door being less than said latched resistance,said lug means engaging at least one of said projections on saidarcuately movable member when said latch means is in said latchedcondition whereby said carriage is transported in said first lineardirection along said guideway, said stop means thereafter preventingfurther movement of said carriage in said first linear direction wherebysaid lug means overcomes the latched resistance to movement of saidarcuately movable .member and said arcuately movable member rotatesslightly .thus moving said latch means to the unlatched condition andthus permitting relative movement between said chain and said carriage,means for de-energizing said power source whereby .movement of saidchain ceases, means for re-energizing said power source whereby said lugmeans is carried around said first sprocket wheel and into position andto traverse said second straight run portion in saidsecond substantiallylinear directions, resistance to movement of said carriage and said doorbeing greater than said'unlatched resistance, said lug means engaging atleast oneprojection thereby moving said-arcuately movable member into .alatched condition and thereby engaging another projection with said lugrneans,.thereafter the movementiof said lug means in said secondsubstantially linear direction transports said carriage in said secondlinear direction until said stop means limits further movement of saidcarriage in said guideway.

7. .A latching mechanism to connect and disconnect a carriage from acontinuous chain comprising, a rotatable member having a first surfaceand mounted for rotation about an axis, teeth extending from saidrotatable member, said first surface having arcuate portions and lockingportions, a lug carried by the chain, a holding member having. a firstsurface, means urging said holding member toward said arcuate and saidlocking portions, said first surface of said holding member engagingsaid locking portion when the latching mechanism is in.the connectedposition, said lug engaging at least one of said teeth in the connectedposition thereby moving said carriage, a stop coactingwith said carriagewhereby said carriage is prohibited from movement and thereafter a forceexertedby the lug to said tooth rotates said rotat able member therebyputting the latching mechanism in the disconnected position whereby thefirst surface of said holding member engages said arcuate portion.

'8. A latching mechanism for effecting relative movement between a firstand a second membercomprising, a latch assembly carried by said secondmember and including a rotatable member having first and secondalternately spaced surface portions, tooth means extending from saidrotatable member, a holding member having surface means adapted toengage said first and second alternately spaced surface portions, meansurging said plunger toward said rotatable member, engagement of saidsurface means of said holding member and said' first and second surfaceportions creating a latched and an unlatched resistance to rotation ofsaid rotatable member, a first and a second lug carried by said firstmember and adapted to surround said tooth means whereby movement of saidfirst member is transmitted to said second member while the resistanceto movement of said second member is less than said latched resistance,when the resistance to movement of said second member becomes greaterthan said latched resistance said rotatable member rotates therebyallowing relative movement between said first and second members.

9. A latching mechanism to connect and disconnect a carriage from acontinuous chain comprising, a first member having a first surface andmounted for rotation about an axis, teeth extending from said member,said first surface having alternately spaced arcuate portions andlocking portions, a first and a second lug carried by the chain, aplunger having a first surface, spring means urgingsaid holding membertoward said rotatable member, said first surface of said holding memberengaging said locking portion when the latching mechanism is in theconnected position, said first and second lugs surrounding one of saidteeth and thereby moving said carriage when said latching mechanism isin the connected position, stop means forcing said carriage to stopwhereby a force exerted by the chain through at least one of said lugsto the said tooth rotates said rotatable member thereby putting thelatching' mechanism in the disconnected position whereby thefirst-surface of said plunger engages said arcuate portion.

References Cited in the file of this patent UNITED STATES PATENTS

